mitsubishi WS-55907 convergence and video

[Guest]

Hi. Got a Mits WS-55907 here. Odd problem if they are linked somehow,
otherwise 2 separate problems.

Anyway, first off, I will replace the convergence STK392-570 chips, as I
have good power to them.

Now for the odd part - no video, but does show the closed caption speech.
Also, no access to menu, just goes blank raster. Video good at rear jack
panel, but doesn't get to video drive transistors.

I did solder up rear jack panel and board connectors, which often fixes no
video, but not this one.

I did clean a bit of tube oil from signal board, but it appeared none had
traveled to or under any chips, was a small localised spot. Cleaned with
alcohol. No effect on video.

I have tube set and board set sprawled out on bench so I can run them up,
and find no missing voltages. All look clean, no grass or waving. Just this
oddity of no video.

I can give more details of voltages and such if needed, just wondering if
anyone else has seen this, are the two problems linked, or 2 separate
problems. Guy didn't say anything about convergence when I arrived, although
I noticed it right away. He just said video faded away.

Thanks in advance, Danny

 

[Guest]

replaced signal board and stk chips. fixed

 

[Guest]

Should have posted the fix earlier than now, but anyway, replaced signal
board with good used one from thrift store tv. 4 months later, still humming
along.